|Publication number||US3956604 A|
|Application number||US 05/480,931|
|Publication date||May 11, 1976|
|Filing date||Jun 19, 1974|
|Priority date||Jun 26, 1973|
|Also published as||DE2428865A1|
|Publication number||05480931, 480931, US 3956604 A, US 3956604A, US-A-3956604, US3956604 A, US3956604A|
|Inventors||Hans Larker, Jan Nilsson|
|Original Assignee||Allmanna Svenska Elektriska Aktiebolaget|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (7), Classifications (15)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
In apparatus working with high pressure, for example containers in extrusion presses where the working pressure can be of the order of magnitude of 1000 - 2000 MPa, leakage past a seal often causes serious secondary damage if the leakage is not discovered and the press stopped in time. That severe damage may arise is easily understood if it is considered that the hydraulic power at the time may be 1 MW and that, in the event of leakage, a considerable part of this power is exerted in the few mm2 which correspond to the leak. Further, it is difficult to determine from the outside if leakage occurs with the help of the pressure time curve for the main piston as this curve, in case of leakage, normally has the same appearance as when extrusion is taking place.
The present invention relates to a high pressure apparatus having a means for detecting leakage with a minimum loss of time. It comprises a collecting space for leaking pressure medium located outside a high pressure seal. The space is provided or communicates with detectors for sensing a temperature or pressure increase in the space caused by leaking pressure medium, for example oil. At a certain pressure or temperature the detector releases a signal and/or stops the press.
One embodiment of the invention appears from the FIGS. 1 to 5, where
FIG. 1 shows a detail of a hydraulic pressure press and
FIG. 2 a section on the line A -- A of FIG. 1.
FIG. 3 shows an enlargement of the portion B encircled in FIG. 1;
FIG. 4 is an enlarged cross-section through the wire; and
FIG. 5 shows the wire in broken condition.
In FIG. 1, 1 designates the high pressure cylinder of the press and 2 a piston insertable into said cylinder. A seal 3 is arranged around the piston and kept in position by a seal holder 4. The space at the upper part of the high pressure cylinder 1, which is defined by the piston 2, the seal holder 4 and the cylinder 1, is called the sealing zone. In this zone two sealing rings 5 and 6 and a packing 7 of elastic material, for example an O-ring of rubber, are located. Outside the sealing rings 5 and 6 and between the cylinder 1 and the seal holder 4 there is formed the space 9 which collects pressure medium leaking out from the press between the engaging surfaces of the high pressure cylinder and the seal holder. This space 9 is sealed outwardly by means of, for example, an electric cable 10. When the oil leaking out causes the pressure in the space 9 to rise above a certain limit, the cable 10 is broken, an electric current through the cable being thereby interrupted and a signal being emitted and/or the press being stopped.
The device is suitably provided with a narrow channel 11 through the sealing sleeve 12. This channel prevents a very moderate leakage or an elastic deformation of the space 9 to cause a false alarm.
Alternatively, the space 9 can be sealed off by means of some other member instead of the cable 10 and be connected to a pressure-sensing breaker (not shown) through a channel 13. Temperature-sensitive elements can also be positioned around the circumference of the cylinder 1, for example in the space 9, for detecting leakage past the sealing ring 5 or in space 14 in case of leakage at the inner sealing ring 6. The last-mentioned leakage can also be detected by means of the other sensing members mentioned in the description. The device according to the invention can of course be used in other types of high pressure seals than the one described above, with certain constructional adjustments.
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4129759 *||Jul 16, 1976||Dec 12, 1978||Hug Alfred J T||Pressure responsive circuit interrupter|
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|US8020576 *||Mar 20, 2007||Sep 20, 2011||Delaware Capital Formation, Inc.||Emergency shutoff valve for use in a fuel dispensing system|
|US8066024||Jul 9, 2009||Nov 29, 2011||Delaware Capital Formation, Inc.||Emergency shutoff valve for use in a fuel dispensing system|
|U.S. Classification||200/61.08, 73/40, 100/99, 137/67|
|International Classification||G01M3/32, G01M3/16, B21C23/21, B21C31/00, G01M3/04, F17D5/02|
|Cooperative Classification||F17D5/02, Y10T137/1624, B21C31/00|
|European Classification||B21C31/00, F17D5/02|